From inside (document excerpt):
58CTA/58CTX 2 Stage Deluxe Induced-Combustion 4-Way Multipoise Furnace Installation, Start-up, Operating, and Service and Maintenance Instructions -Series 120 THE PERFORMANCE 80 GAS FURNACE The 58CTA/CTX Two-Stage, 4-way Multipoise Gas Furnaces offer unmatched comfort in their class with ComfortHeatTM Technology in an 80% AFUE gas furnace. You get the benefits of a ComfortHeatTM Technology furnace: reduced drafts, reduced sound levels, longer cycles, less temperature swings between cycles, and less temperature differences between rooms.
Its exclusive, intelligent microprocessor control adapts to the heating needs of the home by automatically adjusting high and low heat times to maximize comfort. The 58CTA/CTX furnaces are approved for use with natural or propane gas, and the 58CTX is also approved for use in Low NOx Air Quality Management Districts. CERTIFIED ® STANDARD FEATURES – ComfortHeatTM Technology Two-stage heating with single-stage thermostat Very low operating sound through low-stage operation and QuieTechTM system – Media Filter Cabinet Available – Microprocessor based “smart ” control center Adapts heating stages to meet demand Dehumidification selection for summer-time cooling Adjustable heating air temperature rise Adjustable cooling airflow ComfortFanTM–Constant fan speed selectable from thermostat LED diagnostics and self test feature Stores fault codes during power outages – 4-way Multipoise furnace, 13 vent applications – Power HeatTM Igniter – Draft safeguard switch to ensure proper furnace venting – All Models Chimney-Friendly when used with the accessory vent kit. – Insulated blower compartment – Heat pump compatible – Residential installations eligible for consumer financing through the Retail Credit Program – Twinning in Upflow, Downflow and Horizontal LIMITED WARRANTY – 20-year warranty on “Super STM ” heat exchanger – 5-year parts warranty on all other components Form No./Catalog No. 58CT-6SI 11-05 2-Stage Deluxe Induced-Combustion 4-Way Multipoise Furnace Cancels: II312A-45-4/58CT-5SI 58CT-6SI/II312A-45-5 10-05 Installation, Start-up, Operating, and Service and Maintenance Instructions Series 120/C NOTE: Read the entire instruction manual before starting the installation. This symbol indicates a change since the last issue. Portions of the text and tables are reprinted from NFPA 54/ANSI Z223.1-2006, with permission of National Fire Protection Association, Quincy, MA 02269 and American Gas Association, Washington DC 20001. This reprinted material is not the complete and official position of the NFPA or ANSI on the referenced subject, which is represented only by the standard in its entirety. TABLE OF CONTENTS SAFETY CONSIDERATIONS .2 INTRODUCTION 3 CODES AND STANDARDS 5 Safety .